House electric



Patented Dec. 28, 1926.

SITES PATENT @FEFEQEZ.

FESTUS L. MINNEAB, OF "WILKINSBUEG, E'ENNSYLVANIA, ASSIGNOE T0 YVEiiTING- HOUSE ELECTRIC 5: HIANUFACTURING CODIPANY, A CORZPOEATION OI PE'NHSYL- VANIA.

COATING IVIETAL PLATES FGB MOLDING.

No Drawing.

This invention relates to a composition adapted to be used for coating metal plates, such as the steel plates used in the molding of micarta board,and, more especially, to an oil composition which will not tarnish the surface of the steel.

Micarta board is a material composed. generally of layers of paper or similar material which have been impregnated with a binder, generally a phenolic condensation product, the several layers constituting the board having then been compressed and heattreated in amold. In order to utilize a single mold for the simultaneous production of several boards by compressing and heattreating the material, a number of such boards, each formed of several layers of impregnated material, are stacked alternately with steel plates in the mold and pressure and heat applied. The steel plates serve to separate the individual boards so that, after pressing and curing in the mold, the completed boards may be readily removed.

In order to prevent micarta boards from adhering to the surface of the steel plates, a composition is generally applied to the surface of the plates between which the micarta material is pressed and baked. Previously, compositions, such as linseed or other vegetable oils or a mixture of the same with machine oil. were used for this purpose. Such oils or greases act well in preventing the adhesion of micarta board to steel, but, at the high temperatures used (150 to 180" C.) in the curing, and under the high pressure (1000 lbs. per sq. in.) utilized in mold ing, carbonization takes place, leaving a dark-colored or black deposit on the surface of the steel plate.

Even a single application of such a con1-- position on a new plate is snliicient to discolor its surface and, in a short time, the plate must be discarded since, when blaclrened, it is very difficult to prevent sticking of the miearta board thereto. By reason of the accumulated deposit of carbon or other organic matter on the surface of the steel, a dull finish is given to the micarta board. In order to prolong the life of the steel plates, much extra labor was necessary to keep them in good condition.

The present invention obviates these difliculties, it being among the objects thereof derise a coinpesitinn which relatively Application filed August 17, 1920. Serial No. 4.04.208.

inexpensive; which will not tarnish the plates, and which will prevent the molded boards from adhering to the plates. I have found that, by adding an oxidizer to the composition. the deposition of carbon is prevented, tarnishing of the steel plates is prevented and the micarta board is given a bright finish.

I believe that the oxidizer, under the temperatures of curing, liberates oxygen which oxidizes the carbon to carbon monoxide or dioxide as fast as it is formed from the decomposition of the organic oils, greases, or other ingredients utilized in the making of the micarta board.

Although a large number of oils or in the composition, and I may use any one of a number of well known oxidizers. I preferably use one that is not dangerous to handle and one which, at the same time, will give off sufiicient oxygen to oxidize the carbon formed under the conditions of temperature and pressure utilized in the making of the board. I have found that red lead (Pb OQ is a very satisfactory oxidizer for my purpose. A specific composition which I have found well adapted for applying to the steel plates comprises a mixture of 8 parts boiled linseed oil with 4 parts red lead (minimum), by weight.

Excellent results have been obtained by the use of such a mixture of linseed oil and red lead on the plates. The plates remain bright and clean and, consequently, give good polished surface to the micarta board. The board not only has a high degree of polish but is not discolored by the treatment. The life of the steel plates is prolonged indefinitely and it is only necessary to replace these plates when they become damaged accidently, as by denting.

Although I have described the use of a mixture of linseed oil and red lead in my composition, it is to be understood that various oils, fats, greases or waxes such as stearin, either vegetable or minerai, be

utilized, in my process, and, in the claims, the term oil is used to include such materials. As oxidizing materials, the various oxides of lead are suitable, as are manganese dioxide, potassium chlorate, and other Wellknown oxidizers.

Having thus fully described my said invention, What I claim as new and desire to secure by Letters Patent is 1. In a method of molding, the step which comprises coating-a metal :body with a composition containing an oil and an oxidizer to prevent tarnishing of said body.

2. In amethod of molding, the step which comprises coating a 'metal body with a composition containing an oil'and an oxidizer capable of liberating sufficient oxygen to oxidize the carbon deposited by'the deconn position of greases or oils or condensation vproducts at high temperatures.

3. In a method of molding, the step which comprises coating a metal body with a composition containing a vegetable oil and an oxidizer to prevent tarnishing of said body.

4. In a method of'molding, the step which comprises coating a metal body/with a com position containing a vegetable-oil and red lead to prevent tarnishing of said body.

5. In a inethodof molding, the step which comprises coating a metal body with a composition containing linseed oil and red lead to prevent tarnishing of said body.

(5] In a method of molding,'tl'1e step which comprises coating" a metal body with a coinposition containing eight parts of boiled linseed oil and about :four parts of'red lead by weight to preventtarnishing of said body.

In testimony whereof, I have hereunto subscribed my name this 5th day'of August,

FESTUSL. MINNEA'R. 

